BiologyICSE Class 10 · Population

Demography: Population Density, Birth Rate, Death Rate and Growth Rate (ICSE Class 10)

Updated 16 October 2026 · Fact-checked

Demography is the statistical study of human populations. Birth rate (natality) is the number of live births per 1000 people per year, and death rate (mortality) is the number of deaths per 1000 people per year. Growth rate is birth rate minus death rate. Population density is the number of people per square kilometre.

Growth rate is what is left when deaths are taken from births: 22 − 8 = 14 per 1000 a year, and dividing by 10 gives 1.4%.

Illustration drawn for QuestionBuddy.

Understand Demography: Birth Rate, Death Rate and Growth Rate

Demography. Demography is the statistical study of human populations: their size, density, distribution, birth rates, death rates, and age and sex composition. Governments use these figures to plan schools, hospitals, food supply, housing and jobs.

The five terms in the syllabus.

Term	Meaning	Unit
Population density	number of people living in a unit area	people per km²
Birth rate (natality)	number of live births per 1000 people per year	per 1000 per year
Death rate (mortality)	number of deaths per 1000 people per year	per 1000 per year
Growth rate	birth rate − death rate (ignoring migration)	per 1000 per year, or %

Every word in a definition carries marks: 'live births', 'per thousand', 'per year'.

Calculations.

Birth rate = live births in a year ÷ population × 1000
Death rate = deaths in a year ÷ population × 1000
Growth rate = birth rate − death rate (per 1000 per year)
Growth rate as a percentage = (growth rate per 1000) ÷ 10
Population density = population ÷ area (km²)

Example: if birth rate is 22 and death rate is 8 per 1000, the growth rate is 14 per 1000 per year, or 1.4% per year.

Reading the rates.

If the birth rate is higher than the death rate, the population grows; if they are equal, it is stable (zero growth); if the death rate is higher, it shrinks.
A low death rate usually means good medical care, vaccination, nutrition and sanitation.
The natural growth rate uses only births and deaths. In a real town, people also move in (immigration) or out (emigration); a question will say if migration must be included.

Density is not the same as overpopulation. A crowded city with enough water, food and jobs may cope with a high density; a dry region with a low density may still be overpopulated if its resources cannot support even those few people.

Why rates, not totals? Expressing births and deaths per 1000 lets us compare places of very different sizes. A city may record more births than a village simply because it has more people; its birth rate may still be lower.

Demography: Birth Rate, Death Rate and Growth Rate: key facts

Rates: $B i r t h r a t e = l i v e bi r t h s ina y e a r \div p o p u l a t i o n \times 1000∣ D e a t h r a t e = d e a t h s ina y e a r \div p o p u l a t i o n \times 1000∣ G r o w t h r a t e = bi r t h r a t e - d e a t h r a t e$; All per 1000 people per year.
Percentage and density: $G r o w t h r a t e$; Density in people per km².
Terms: $N a t a l i t y = bi r t h r a t e ∣ M or t a l i t y = d e a t h r a t e ∣ D e m o g r a p h y = s t a t i s t i c a l s t u d y o f h u man p o p u l a t i o n s$; Natal: birth; mortal: death.

How to answer Demography: Birth Rate, Death Rate and Growth Rate questions

Population numericals use one division and one multiplication by 1000; keep the units with every answer.

1Write down the population, the number of live births and the number of deaths for one year.
2Divide births by the population and multiply by 1000 for the birth rate; do the same for deaths.
3Subtract to get the growth rate per 1000; divide by 10 for a percentage.
4For density, divide the population by the area in km².
5Write the unit: 'per 1000 per year' or 'people per km²'.
6Include migration only if the question gives it.

Demography: Birth Rate, Death Rate and Growth Rate in real life

The idea, met in an everyday situation. Answer the question in your own words, then compare with the model answer. The one-line hook is what to remember.

A ward's annual report

Suppose your municipal ward report says: population 32,000; live births last year 576; deaths 224.

By how many people did the ward grow last year, and what was its growth rate as a percentage?

Try it first, then show the solutionSolution

Natural increase = 576 − 224 = 352 people.
Growth rate = 352 ÷ 32,000 × 100 = 1.1% per year.
Check with rates: birth rate 576 ÷ 32 = 18 and death rate 224 ÷ 32 = 7 per 1000, so growth = 11 per 1000 = 1.1%.

Answer: 352 more people; growth rate 1.1% per year (11 per 1000).

Memory hook: Divide, times a thousand, then subtract.

More births, lower rate

Imagine a hill village of 5,000 people records 150 live births in a year, while a city of 5,00,000 records 9,000.

Which place has more births, and which has the higher birth rate?

Try it first, then show the solutionSolution

Village: 150 ÷ 5,000 × 1000 = 30 per 1000.
City: 9,000 ÷ 5,00,000 × 1000 = 18 per 1000.
The city has 60 times as many births but a lower birth rate, because its population is 100 times larger.

Answer: The city has more births; the village has the higher birth rate (30 against 18 per 1000).

Memory hook: Totals mislead; rates compare.

Tricks to remember Demography: Birth Rate, Death Rate and Growth Rate

Short memory aids. Say each one aloud once, then use it on a question the same day.

Natal and mortal
Natal = birth (as in 'prenatal'); mortal = death: natality is birth rate, mortality is death rate.
Use it when: The two terms.
Live, thousand, year
Every birth-rate definition needs three words: live births, per thousand, per year.
Use it when: Full-mark definitions.
Births minus deaths
Growth = B − D; divide by 10 for a percentage.
Use it when: Growth-rate sums.

Demography: Birth Rate, Death Rate and Growth Rate: solved examples

Ordered from board level to HOTS. Try each one before you open the solution.

Example 1: A village birth rate · 1 mark · MCQBoard level

A village of 4,000 people has 100 live births in a year. Its birth rate is:
(a) 2.5 per 1000 per year
(b) 25 per 1000 per year
(c) 40 per 1000 per year
(d) 250 per 1000 per year

Try it first, then show the solutionSolution

Birth rate = 100 ÷ 4,000 × 1000 = 25 per 1000 per year.

Answer: (b) 25 per 1000 per year

Example 2: Birth and death rates · 2 marks · Short answerBoard level

A town of 1,20,000 people records 2,640 live births and 960 deaths in one year. Calculate its birth rate and death rate.

Try it first, then show the solutionSolution

Birth rate = 2,640 ÷ 1,20,000 × 1000 = 22 per 1000 per year. (1)
Death rate = 960 ÷ 1,20,000 × 1000 = 8 per 1000 per year. (1)

Answer: Birth rate 22, death rate 8 (per 1000 per year)

Example 3: Growth, density and next year's population · 3 marks · Short answerHarder board level

For the same town (1,20,000 people, 2,640 births, 960 deaths, area 300 km²), find (a) the growth rate per 1000 and as a percentage, (b) the population density, (c) the population after one year, ignoring migration.

Try it first, then show the solutionSolution

(a) 22 − 8 = 14 per 1000 per year = 1.4%. (1)
(b) 1,20,000 ÷ 300 = 400 people per km². (1)
(c) 1,20,000 + 2,640 − 960 = 1,21,680. (1)

Answer: (a) 14 per 1000 (1.4%) (b) 400 per km² (c) 1,21,680

Example 4: Finding the death rate · 2 marks · Short answerHarder board level

A district has a birth rate of 30 per 1000 per year and a growth rate of 1.8% per year (no migration). Find its death rate.

Try it first, then show the solutionSolution

1.8% = 18 per 1000. (1)
Death rate = 30 − 18 = 12 per 1000 per year. (1)

Answer: 12 per 1000 per year

Example 5: Density as a district grows · 3 marks · Short answerHarder board level

District A has 9,60,000 people in 1,200 km². Its population is expected to grow by 1.5% in a year while its area stays the same. (a) Find its density now. (b) Find its density after one year. (c) State one problem the district is likely to face as it becomes more crowded.

Try it first, then show the solutionSolution

(a) 9,60,000 ÷ 1,200 = 800 people per km². (1)
(b) Population after a year = 9,60,000 × 1.015 = 9,74,400; density = 9,74,400 ÷ 1,200 = 812 people per km². (1)
(c) Shortage of housing (slums), or pressure on water supply and transport. (1)

Answer: (a) 800 per km² (b) 812 per km² (c) e.g. housing shortage

Example 6: Case study: a town with migrants · 3 marks · Case-basedHOTS / competency

Suppose a new industrial town has a birth rate of 18 and a death rate of 7 per 1000 per year. In addition, 3 people per 1000 move into the town each year for jobs, and nobody leaves.
(a) Find the natural growth rate.
(b) Find the actual rate at which the population grows.
(c) Why would planners need both figures?

Try it first, then show the solutionSolution

(a) Natural growth = 18 − 7 = 11 per 1000 per year. (1)
(b) Actual growth = 11 + 3 = 14 per 1000 per year (1.4%). (1)
(c) The natural rate shows the effect of health care and family size; the actual rate tells how many more houses, schools and jobs are needed. (1)

Answer: (a) 11 per 1000 (b) 14 per 1000 (c) Natural shows births and deaths; actual shows total demand.

Where students lose marks in Demography: Birth Rate, Death Rate and Growth Rate

The slips examiners see most often, and what to write instead.

Mistake: Ten years instead of one
CISCE examiners' comments, 2024 Q1(xiv): in an MCQ on birth rate, candidates answered 10 years instead of one year; examiners advised learning definitions with their key words.
Wrong working
Live births per 1000 in 10 years.
Right working
Live births per 1000 people per year.
Do this: All the rates are per year.
Usually costs: 1 mark.
Mistake: Natality called mortality or growth rate
CISCE examiners' comments, 2025 Q1(i): for the number of live births per thousand people per year, candidates wrote mortality or population growth rate instead of natality.
Wrong working
Live births per 1000 per year = mortality.
Right working
= natality (birth rate).
Do this: Natal = birth; mortal = death; growth = the difference.
Usually costs: 1 mark.
Mistake: Answer without a unit
A rate of '22' means nothing without 'per 1000 per year'; density needs 'per km²'.
Wrong working
Birth rate = 22.
Right working
Birth rate = 22 per 1000 per year.
Do this: Write the unit after every answer.
Usually costs: ½–1 mark.

Exam tips

Learn each definition with its key words: live births, per 1000, per year, per km².
Show the division and the × 1000 in your working.
Convert a percentage growth rate to 'per 1000' by multiplying by 10.
Ignore migration unless the question gives it.

Practice questions on Demography: Birth Rate, Death Rate and Growth Rate

Write each answer on paper first. Open the hint only if you are stuck, and the answer only when you have finished.

Q1 · 1 mark · MCQBoard level
A growth rate of 2.1% per year is the same as:
(a) 2.1 per 1000 per year
(b) 21 per 1000 per year
(c) 210 per 1000 per year
(d) 0.21 per 1000 per year
Hint
Multiply a percentage by 10.
Answer
(b) 21 per 1000 per year
Q2 · 1 mark · Very short answerBoard level
A village of 3,500 people records 84 live births and 3 stillbirths in a year. Find its birth rate.
Hint
Only live births count.
Answer
Birth rate = 84 ÷ 3,500 × 1000 = 24 per 1000 per year (stillbirths are not counted).
Q3 · 1 mark · Very short answerBoard level
A town of 45,000 people has a death rate of 6 per 1000 per year. How many deaths occur there in a year?
Hint
Reverse the formula.
Answer
45,000 × 6 ÷ 1000 = 270 deaths.
Q4 · 2 marks · Short answerHarder board level
In a country both the birth rate and the death rate fall by 4 per 1000 over ten years. What happens to the growth rate? Explain with an example.
Hint
Subtract both ways.
Answer
It stays the same, since both terms fall equally. For example, 26 − 10 = 16 and 22 − 6 = 16 per 1000.
Q5 · 2 marks · Short answerHarder board level
A town of 75,000 people has a death rate of 9 per 1000. Planners want its growth rate to be no more than 1.0% per year (no migration). What is the largest number of live births per year that keeps to this?
Hint
1.0% = 10 per 1000.
Answer
Birth rate = 10 + 9 = 19 per 1000; births = 75,000 × 19 ÷ 1000 = 1,425.
Q6 · 2 marks · Short answerHarder board level
Why are births and deaths expressed per 1000 people instead of as total numbers?
Hint
Comparing places of different size.
Answer
Totals depend on the size of the population. Rates per 1000 allow fair comparison between places of different sizes and over different years.
Q7 · 3 marks · Short answerHOTS / competency
Suppose a country has a birth rate of 9 and a death rate of 11 per 1000 per year. (a) Find its growth rate. (b) What is happening to its population? (c) Suggest one reason the death rate might exceed the birth rate.
Hint
The answer can be negative.
Answer
(a) 9 − 11 = −2 per 1000 (−0.2%). (b) It is shrinking (without migration). (c) A large share of old people, so more deaths, while families have few children.
Q8 · 2 marks · Short answerHOTS / competency
A student says, 'A place with a high population density must be overpopulated.' Do you agree? Give a reason with an example.
Hint
Compare people with resources, not with area.
Answer
No. Overpopulation means more people than the resources can support. A dense city with enough water, food and jobs may cope, while a sparsely populated desert area may be overpopulated if its water cannot support even those few people.

Test your recall

Answer in your head or on paper first, then open the card. Pulling an answer out of memory makes it stick far better than re-reading.

1.Term for people moving into a place?Show answer
Immigration.
2.Term for people moving out of a place?Show answer
Emigration.
3.Effect on the growth rate if the death rate falls and the birth rate stays the same?Show answer
The growth rate rises.
4.Density of 50,000 people in 125 km²?Show answer
50,000 ÷ 125 = 400 people per km².
5.Growth rate of 15 per 1000 as a percentage?Show answer
1.5%.

Demography: Birth Rate, Death Rate and Growth Rate: frequently asked questions

What is the difference between population size and population density?

Population size is the total number of people in a place. Population density is the number of people per square kilometre, so it also takes the area into account: a large country can have a low density.

How do you convert growth rate per 1000 into a percentage?

Divide by 10. A growth rate of 14 per 1000 per year is 1.4% per year.

Why does the definition of birth rate say 'live' births?

Only babies born alive add to the population. Stillbirths are not counted, so the definition must say live births per 1000 people per year.